From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EBD60C352A1 for ; Tue, 6 Dec 2022 17:16:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235268AbiLFRQ1 (ORCPT ); Tue, 6 Dec 2022 12:16:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235314AbiLFRQ0 (ORCPT ); Tue, 6 Dec 2022 12:16:26 -0500 Received: from mail-wr1-x42e.google.com (mail-wr1-x42e.google.com [IPv6:2a00:1450:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69124DEA5 for ; Tue, 6 Dec 2022 09:16:25 -0800 (PST) Received: by mail-wr1-x42e.google.com with SMTP id h7so18445647wrs.6 for ; Tue, 06 Dec 2022 09:16:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:from:to:cc:subject:date:message-id:reply-to; bh=5y5pHsTfKWlf6G9xhN6zIJC+yiHVz8mgRid+lBAfjKI=; b=cSBwdOzjkGnRh5BdlBn4eECWGdsafj0JSyCwgySbNNTiYAA7WvDTxqSfKNrb6FeQuk 8fEdgI97uKlziLEWdN32I83u39j+SgVYPH/QHcuspRX2KkD9q9wfqfZ6fLqVYagVG5Lc MBxy9Rapg+Gnxw6+9h3NMylMkv0/wujORFyPwyPsI1pFgDHaAC+JwxmB4kiNOSdcCITU YFCcSiDDaZgwa9h7zoyJlT2RdOL6VOX2BOWOml47fFgo/xiONE2Mn+bztcz6fXoTqqy3 KCess+OuTbSqMukP6CeexUqDQ/5WqQuOGHF0tcRNI3IbIDkojwW7iEjaYam6rFttiWz1 QSPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=5y5pHsTfKWlf6G9xhN6zIJC+yiHVz8mgRid+lBAfjKI=; b=egFfYAJBUtitPc433gHChoz52kKc/FUNShw+rxCbsAtGNadVYI1R7XoK3MJ/7LR1Ju 3PsInqrYxwkHFkoHYq9jzK+FBsFg5mLF398MGs9SMG5n20BGOTJESaWjj+ECvw0FQcsJ 38hFHpZIqSsabLAT/8cqs+SZptXNSzP8x9xOeP/pceUCqX02fMNeb5ga1+jx9pqI2qsA gNU1rSv7RogamZxeys1ho/qmXAreoS7Xa6B10+7hvxBAV9/BzVSM1pWsGsTzLLUTYOJi G8BkwQX3SVInuELHGtVLuPwNBp31pkOmJz4m8nU8nB6GzJZ2kRCbsOWVLnUIx6qvlAAr +CHQ== X-Gm-Message-State: ANoB5pmlUTKIWos1s2fAKpW/Tmx0J2xFS66Sg4CVqr0wGCPwHlrLMVx1 MtjDja8JKFYuf3+XO9Tm2Qnle8u8zxcJdfR+ X-Google-Smtp-Source: AA0mqf43yyiyCx+eRgcDtKaL/MGiZCM90oVb4NCLMpkwNbV2ruxbQtxgvOz9Fz4Ilwk3iiQbbBJKVg== X-Received: by 2002:a05:6000:1e0c:b0:242:3fa4:820d with SMTP id bj12-20020a0560001e0c00b002423fa4820dmr12591498wrb.564.1670346983906; Tue, 06 Dec 2022 09:16:23 -0800 (PST) Received: from localhost ([2a00:79e0:9d:4:d775:c942:f0bf:947f]) by smtp.gmail.com with ESMTPSA id z10-20020adfec8a000000b00236576c8eddsm17309207wrn.12.2022.12.06.09.16.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Dec 2022 09:16:23 -0800 (PST) From: Jann Horn To: stable@vger.kernel.org Subject: [PATCH stable 4.9,4.14 1/2] mm/khugepaged: fix GUP-fast interaction by sending IPI Date: Tue, 6 Dec 2022 18:16:02 +0100 Message-Id: <20221206171614.1183048-1-jannh@google.com> X-Mailer: git-send-email 2.39.0.rc0.267.gcb52ba06e7-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 2ba99c5e08812494bc57f319fb562f527d9bacd8 upstream. Since commit 70cbc3cc78a99 ("mm: gup: fix the fast GUP race against THP collapse"), the lockless_pages_from_mm() fastpath rechecks the pmd_t to ensure that the page table was not removed by khugepaged in between. However, lockless_pages_from_mm() still requires that the page table is not concurrently freed. Fix it by sending IPIs (if the architecture uses semi-RCU-style page table freeing) before freeing/reusing page tables. Link: https://lkml.kernel.org/r/20221129154730.2274278-2-jannh@google.com Link: https://lkml.kernel.org/r/20221128180252.1684965-2-jannh@google.com Link: https://lkml.kernel.org/r/20221125213714.4115729-2-jannh@google.com Fixes: ba76149f47d8 ("thp: khugepaged") Signed-off-by: Jann Horn Reviewed-by: Yang Shi Acked-by: David Hildenbrand Cc: John Hubbard Cc: Peter Xu Cc: Signed-off-by: Andrew Morton [manual backport: two of the three places in khugepaged that can free ptes were refactored into a common helper between 5.15 and 6.0; TLB flushing was refactored between 5.4 and 5.10; TLB flushing was refactored between 4.19 and 5.4; pmd collapse for PTE-mapped THP was only added in 5.4] Signed-off-by: Jann Horn --- include/asm-generic/tlb.h | 6 ++++++ mm/khugepaged.c | 2 ++ mm/memory.c | 5 +++++ 3 files changed, 13 insertions(+) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 5e7e4aaf36c5..43409a047480 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -60,6 +60,12 @@ struct mmu_table_batch { extern void tlb_table_flush(struct mmu_gather *tlb); extern void tlb_remove_table(struct mmu_gather *tlb, void *table); +void tlb_remove_table_sync_one(void); + +#else + +static inline void tlb_remove_table_sync_one(void) { } + #endif /* diff --git a/mm/khugepaged.c b/mm/khugepaged.c index f426d42d629d..f67c02010add 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1046,6 +1046,7 @@ static void collapse_huge_page(struct mm_struct *mm, _pmd = pmdp_collapse_flush(vma, address, pmd); spin_unlock(pmd_ptl); mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); + tlb_remove_table_sync_one(); spin_lock(pte_ptl); isolated = __collapse_huge_page_isolate(vma, address, pte); @@ -1295,6 +1296,7 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) _pmd = pmdp_collapse_flush(vma, addr, pmd); spin_unlock(ptl); atomic_long_dec(&mm->nr_ptes); + tlb_remove_table_sync_one(); pte_free(mm, pmd_pgtable(_pmd)); } up_write(&mm->mmap_sem); diff --git a/mm/memory.c b/mm/memory.c index 615cb3fe763d..0136af15ba18 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -373,6 +373,11 @@ static void tlb_remove_table_smp_sync(void *arg) /* Simply deliver the interrupt */ } +void tlb_remove_table_sync_one(void) +{ + smp_call_function(tlb_remove_table_smp_sync, NULL, 1); +} + static void tlb_remove_table_one(void *table) { /* base-commit: 179ef7fe86775fe32bd1bfe791887d1994ddcfb0 -- 2.39.0.rc0.267.gcb52ba06e7-goog